Homogeneous olefin polymerization catalyst composition

ABSTRACT

The present invention relates to an olefin polymerization catalyst composition comprising a metallocene and an aluminoxane containing alkyl groups with at least two (2) carbon atoms which provides more uniformity than methylaluminoxane, offers greater control and reproducibility of olefin polymerization and greater storage stability. The present invention also provides a method for the preparation of the olefin polymerization catalyst composition.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/FI98/00077 which has an Internationalfiling date of Jan. 27, 1998 which designated the United States ofAmerica. New homogeneous olefin polymerization catalyst composition

The present invention relates to an olefin polymerization catalystcomposition, in particular a composition comprising a metallocene and analuminoxane or a reaction product thereof. The invention also relates toa process for preparing such an olefin polymerization catalystcomposition and to the use of such an olefin polymerization catalystcomposition for the polymerization of olefins.

In many olefin polymerization processes using a single site catalyst,homogeneous catalyst compositions based on a metallocene procatalyst andan aluminoxane cocatalyst have been used. By “homogeneous” is in thispaper meant a dissolved or liquid catalyst, or a catalyst obtained byprecipitation, evaporation or crystallization from solution or bysolidification of liquid (e.g. melt).

According to S. Srinvasa Reddy, Polymer Bulletin, 36 (1996) 317-323, thepolymerization activity of tetraisobutyldialuminoxane cocatalyst wasclearly lower than the activity of methylaluminoxane cocatalyst. Thisreflects the prevailing general opinion, that only methyl aluminoxane asa cocatalyst gives satisfactory polymerization catalyst activities.

We have now surprisingly found that olefin polymerization may be carriedout effectively using as a catalyst the combination of a metallocene andan aluminoxane other than methylaluminoxane where the metallocenecontains a ring-substituted homo- or heterocyclic cyclopentadienylsandwich ligand.

Thus viewed from one aspect the invention provides an olefinpolymerization catalyst composition comprising a metallocene and analuminoxane or a reaction product thereof, characterized in that saidmetallocene contains a ring-substituted homo- or heterocycliccyclopentadienyl sandwich ligand and in that said aluminoxane containsalkyl groups containing at least two carbon atoms.

The catalyst composition of the invention is particularly advantageoussince higher alkyl aluminoxanes, i.e. aluminoxanes containing alkylgroups containing at least 2 carbon atoms, may be prepared which aremore uniform and more readily characterizable than methylaluminoxane, amaterial which is generally a mixture of several linear or cyclicstructures. Use of more readily characterized aluminoxane co-catalystsoffers the possibility of greater control and reproducibility of olefinpolymerization. Also the storage stability of higher aluminoxanes ismuch better. The structure of the higher aluminoxanes will not changeduring storage, which is the case with MLAO.

The higher alkyl aluminoxane used according to the invention preferablycontains C₂₋₁₀ alkyl groups. especially branched alkyl groups, e.g.ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, i-butyl,n-pentyl, iso-amyl, sec-amyl, tert-amyl, iso-hexyl, sec-hexyl, ortert-hexyl groups. Particularly preferably the higher alkyl aluminoxanecontains C₃₋₆ alkyl groups, especially branched alkyl groups.

The metallocene used according to the invention preferably includes acatalytically active transition metal or lanthanide complexed by one ormore, e.g. 1 or 2 homo- or heterocyclic cyclopentadienyl ligands. Wherethe metallocene contains more than one cyclopentadienyl ligand moiety,then a non ring-substituted cyclopentadienyl ligand moiety may bepresent. However it is preferred that all the cyclopentadienyl ligandmoieties be ring-substituted.

Ring substitution may be for example by pendant groups (e.g. hydrocarbylor hydrocarbyloxy groups optionally attached via heteroatoms such as O,N, S, P, Si or Ge or via multiply bonded carbon atoms), by fused rings(e.g. such as to produce fused bicyclic or polycyclic structures with 5-and 6 membered homo- or heterocyclic rings, which (other than one fivemembered ring) may be saturated or unsaturated, e.g. indenyl,tetrahydroindenyl, fluorenyl and octahydrofluorenyl groups), by bridginggroups attached to the metal or to a second optionally ring-substitutedhomo- or heterocyclic cyclopentadienyl ring (for example with the linkermoiety providing at least one backbone atom selected from carbon,silicon, oxygen, sulphur, nitrogen and phosphorus, e.g. being analkylene or silylene bridge), or by combinations of such substituents,for example with bridging or pendant groups being attached to ringsfused to the cyclopentadienyl ligand moiety rather than directly to thecyclopentadienyl ring.

The ring substituent(s) on the cyclopentadienyl ring are preferably suchas to permit an extension to the π-electron system of thecyclopentadienyl ring, especially preferably such as to further dispersethe negative charge on the ring; thus the ring is especially preferablysubstituted by π-electron withdrawing groups, e.g. polyatomic groupsattached via heteroatoms such as O, S, N or P or via multiple bondedcarbons.

The catalyst composition of the invention may comprise the metalloceneand the higher alkyl aluminoxane either unreacted or more preferably astheir reaction product. The metallocene, aluminoxane ormetallocene:aluminoxane reaction product may if desired be on aparticulate support, e.g. a porous inorganic or inorganic material (e.g.silica) or alternatively they may be in solution in an organic solvent.If desired, one of the metallocene and the aluminoxane may be on aparticulate support with the other present as a solid, as a liquid or insolution. If desired the metallocene and aluminoxane may be brought intocontact only in the olefin polymerization reactor or while being dosedinto the reactor.

Viewed from a further aspect the invention provides the use of analuminoxane containing alkyl groups containing at least two carbon atomsas a co-catalyst with a metallocene pro-catalyst containing aring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligandfor the polymerization of an olefin.

Viewed from another aspect the invention provides the use of ametallocene containing a ring-substituted homo- or heterocycliccyclopentadienyl sandwich ligand as a pro-catalyst with an aluminoxaneco-catalyst containing at least two carbon atoms for the polymerizationof an olefin.

Viewed from a still further aspect the invention provides the use as acatalyst for olefin polymerization of the reaction product of analuminoxane containing alkyl groups containing at least two carbon atomsand a metallocene containing a ring-substituted homo- or heterocycliccyclopentadienyl sandwich ligand.

Viewed from a yet still further aspect the invention provides a processfor the preparation of an olefin polymerization catalyst, said processcomprising contacting a metallocene pro-catalyst containing aring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligandwith an aluminoxane containing alkyl groups containing at least twocarbon atoms, preferably in an organic solvent or solvent mixture inwhich said metallocene and aluminoxane are soluble and optionally in thepresence of a porous particulate support, and if desired recovering thereaction product of said metallocene and aluminoxane, preferablysupported on said particulate support.

Viewed from a yet still further aspect the invention provides a methodof olefin polymerization comprising contacting an olefin with ametallocene:aluminoxane catalyst composition, characterized in that assaid catalyst composition is used a metallocene pro-catalyst containinga ring-substituted homo- or heterocyclic cyclopentadienyl sandwichligand and an aluminoxane co-catalyst containing alkyl groups containingat least two carbon atoms or the reaction product thereof.

Thus using the present invention one may replace MAO as the olefinpolymerization co-catalyst in homogeneous catalyst compositions.Moreover, using the present invention one may produce a homogeneousolefin polymerization catalyst composition suitable for use in gasphase, slurry phase or liquid/solution phase polymerizations.

In a preferred embodiment, the process of the invention involvescontacting

a) a metallocene of the general formula (1):

(C_(p)Y_(q))_(m)MX_(n)Z_(o)  (1)

 wherein Cp or each same or different Cp is one of a mono- orpolysubstituted, fused or non-fused, homo- (=iso-) or heterocycliccyclopentadienyl ligand, indenyl ligand, tetrahydroindenyl ligand,fluorenyl ligand, or octahydrofluorenyl ligand, Y or each same ordifferent Y is a substituent at the cyclopentadienyl ring of said Cpligand and is one of an —OR, —SR, —NR₂, —C(H or R)═, or —PR₂ radical, Ror each same or different R being one of a substituted or unsubstitutedC₁-C₁₆ hydrocarbyl group, a tri-C₁-C₈ hydrocarbylsilyl group, atri-C₁-C₈ hydrocarbyloxy silyl group a mixed C₁-C₈ hydrocarbyl and C₁-C₈hydrocarbyloxy silyl groups, a tri-C₁-C₈ hydrocarbyl germyl group, atri-C₁-C₈ hydrocarbyloxy germyl group or a mixed C₁-C₈ hydrocarbyl andC₁-C₈ hydrocarbyloxy germyl group; M is a transition metal of Group 4 ofthe Periodic Table (IUPAC) and bound to the ligand or ligands Cp atleast in an η⁵ bonding mode; X or each same or different X is bound to Mand is one of a hydrogen, a halogen, a substituted or unsubstitutedC₁-C₈ hydrocarbyl group, a C₁-C₈ hydrocarbylheteroatom (O, S, N, P)group or a tri-C₁-C₈ hydrocarbyl silyl group or two X form together withM a C₄-C₂₀ metallocyclic ring structure; Z is a bridge atom or groupbetween two Cp ligands or between one Cp ligand and the transition metalM; q is, when Cp is unbridged, 0-5 for Cp=cyclopentadienyl, 0-3 forCp=indenyl or tetrahydroindenyl and 0-1 for Cp=fluorenyl oroctahydrofluorenyl, or q is, when Cp is bridged, 0-4 forCp=cyclopentadienyl, 0-2 for Cp=indenyl or tetrahydroindenyl and 0 forCp=fluorenyl or octahydrofluorenyl; m is 1 or 2; m·q≧1; o is 0 or 1; andn is 4-m-o, except when there is a bridge Z between two Cp ligands, inwhich case n is 4-m, and

b) an aluminoxane of one of the following formulas (2):

 (OAIR′)_(p)  (2general)

 wherein each R′ is the same or different and is a C₂-C₁₀ alkyl group;and p is an integer between 1 and 40, and

c) an organic solvent which dissolves said metallocene and saidaluminoxane or a reaction product of them, and recovering saidhomogeneous olefin polymerization catalyst composition.

By mono- or polysubstituted is meant that, in addition to saidsubstituent Y, there may optionally be other substituents at the ringsat said ligand or ligands Cp.

By fused or non-fused is meant that any ring at said ligands may befused or non-fused, i.e. have at least two atoms in common, with atleast one further ring.

By homo- and heterocyclic is meant that any ring of said ligands mayhave only carbon ring atoms (homo- or isocyclic) or may have other ringatoms (e.g. O, N, S, P) than carbon (heterocyclic).

It has thus been realized that a C₂-C₁₀ alkyl aluminoxane (i.e. anon-methyl aluminoxane) can successfully be used as the cocatalyst, if ametallocene having a —OR′, —SR′, —NR′₂, —C(H or R′)═, or —PR′₂substituent at the cyclopentadienyl ring is used as the procatalyst.

According to a non-limiting explanation, an electron pair of theheteroatom (O, S, N, P) or double bond substituents at thecyclopentadienyl ring delocalize it's negative charge and help to ionisethe metallocene, whereby the transition metal M becomes more cationic(electron density deficient). This improves the catalytic interactionbetween the metallocene and the aluminoxane and enables the use ofhigher aluminoxanes like those of the above formula (2). A commerciallyacceptable homogeneous catalyst composition is the result.

According to a preferred embodiment of the invention, thecyclopentadienyl ring is substituted by an organic oxy radical, i.e. Yin the above formula (1) is an —OR radical. According to anotherpreferred embodiment of the invention, the group R of the radical —OR,—SR, —NR₂, —CR═ or —PR₂ is a tri-C₁-C₈ hydrocarbyl silyl group.

According to the process of the present invention said support iscontacted with a metallocene of the general formula (1). It is preferredthat the metallocene of the general formula (1) as group R of saidsubstituent Y has a tri-C₁-C₈ hydrocarbyl silyl or a tri-C₁-C₈hydrocarbyloxy silyl group which are capable of a interaction with saidO, S, N, or P atoms of Y. Most preferred are tri-C₁-C₈ alkyl silylgroups, wherein at least one of the C₁-C₈ alkyls is a branched C₃-C₈alkyl group such as isopropyl, isobutyl, sec-butyl, tert-butyl isoamyl,sec-amyl, tert-amyl, isohexyl, sec-hexyl, or tert-hexyl. Cyclic alkylsand aryls are also preferred groups of the silicone atom.

According to one embodiment of the invention there is only one ligand Cpin the metallocene of formula (1), which preferably is bound to thetransition metal M by both said η⁵ bond and by a bridge Z preferablycontaining a heteroatom such as an N bridge.

However, said metallocene of the general formula (1) has most preferablytwo ligands Cp, i.e. m is 2. According to a still more preferredembodiment, the two Cp ligands are bridged with each other by a bivalentatom or group Z having at least one chain atom which is one of a carbon,silicon, oxygen, sulphur, nitrogen, or phosphorous atom. Mostpreferably, the metallocene of the general formula (1) has m=2, wherebyZ is an ethylene or a silylene bridge.

The transition metal M of group 4 of the Periodic Table in the generalformula (1) is Ti, Zr or Hf, more preferably Zr or Hf, and mostpreferably Zr. The valency or oxidation number of M is 4.

The preferable atom or group X of said metallocene of formula (1) is ahalogen atom and/or a C₁-C₈ hydrocarbyl group. Most preferably, X ischlorine and/or methyl. The number of X atoms or groups, i.e. “n”, ispreferably 1-3, most preferably 2, considering the limitation givenabove for the case when Z is a bridge between Cp and M.

Particularly preferred metallocenes of the general formula (1) arecompounds of following structural formula (3).

wherein each of the Y₁'s and Y₂'s is the same or different and is one ofa hydrogen atom, a halogen atom, an acyl group, an acyloxy group, asubstituted or unsubstituted C₁-C₁₀ hydrocarbyl group, an —OR, —SR, —NR,—C(H or R)═, or —PR₂ radical, R being one of a C₁-C₁₆ hydrocarbyl groupor a tri-C₁-C₈-hydrocarbylsilyl group, provided that at least one of theY₁'s and Y₂'s is one of said —OR, —SR, —NR, —C(H or R)═, or —PR₂radicals; Z is a bivalent atom or group having at least one chain atomwhich is one of a carbon, silicon, oxygen, sulphur, nitrogen orphosphorus atom, preferably 1-4 carbon and/or silicon chain atoms; eachR″ is the same or different and is one of a hydrogen atom, a halogenatom, a C₁-C₁₀ hydrocarbyl group or ring constituent, or a C₁-C₁₀hydrocarbyloxy group, M is one of Ti, Zr or Hf; and X₁ and X₂ are thesame or different and are one of a halogen atom and a C₁-C₈ hydrocarbylgroup. The analogous 4,5,6,7-tetrahydroindenyl derivatives are alsouseful in the invention.

Particularly preferable metallocenes of the formula (1) areethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconium dichloride,ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconium dimethyl,preferably ethylene-bis(2-tert-butyldimetyl(siloxy-indenyl)zirconiumdimethyl, or their corresponding tetrahydroanalogues.

When using chiral metallocenes, they can be used as a racemate for thepreparation of highly isotactic α-olefin polymers. The pure R or S formof said metallocene can also be used, e.g. for the production ofoptically active polymer.

The metallocene of the general formula (1) is usually prepared by aprocess involving repeated deprotonations/metallizations of the aromaticligands and introduction of the bridge Z atom or atoms as well as thecentral atom by their halogen derivatives. The preparation of the saidmetallocene of the general formula (1) can e.g. be carried out accordingto a J. Organometallic Chem. 288 (1958) 63-67 and EP-A-320762, bothherewith incorporated by reference. See also Soares, J. B. P., Hamidec,A. E., Polym. Reaction Eng., 3 (2) (1995) 131-200, herewith incorporatedby reference.

The most preferred metallocenes of the general formula (1), wherein thesubstituent Y is a tri-C₁-C₈ hydrocarbylsiloxy group, is preferablyprepared as follows:

The catalyst compounds according to the invention can be prepared from2- or 3-indanone. In the following, the preparation of 2-siloxy indenederivatives is described to exemplify the preparation of 2- and/or3-siloxy indenes. 2-indanone can be reacted in a suitable solvent with abase and a chlorosilane to form 2-siloxyindene with a yield of over 80%.Suitable solvents are for example dimethylformamide (DMF) andtetrahydrofurane (THF). Suitable bases are for example imidazole andtriethylamine (TEA). Suitable chlorosilanes are for exampletertbutyldimethylchlorosilane, t-hexyldimethylchlorosilane andcyclohexyldimethylchlorosilane. The reaction takes place according tothe following reaction scheme (II):

According to one embodiment of the invention2-tert-butyldimethylsiloxyindene is reacted first with butyllithium andthen with dimethyl dichlorosilane (Me₂SiCl₂) to formdimethylsilylbis(2-tert-butyldimethylsiloxyindene). Butyllithium can bereplaced with methyllithium, sodium hydride or potassium hydride.Likewise dimethyl dichlorosilane can be replaced with any diaLkyl ordiarylsilane. Silicon can be replaced with germanium.

Dimethylsilylbis(2-tert-butyldimethylsiloxyindene) can be reacted withbutyllithium, which gives the corresponding bislithium salt. Thisproduct can be reacted with zirconium tetrachloride to yielddimethylsilylbis(2-tert-butyldimethylsiloxyindenyl)zirconium dichlorideas a mixture of the racemic and meso diastereomers. Butyllithium may bereplaced as described earlier. Zirconium tetrachloride can be replacedwith titanium tetrachloride or hafiium tetrachloride to give thecorresponding titanium and hafiiium complexes. The reactions take placeaccording to the following reaction schemes (III-IV):

According to another embodiment of the invention2-tert-butyldimethylsiloxyindene is reacted first with butylfithium andthen with dibromoethane to formbis(2-tert-butyldimethylsiloxyindenyl)ethane. This compound can bereacted with two equivalents of butyllithium, which gives thecorresponding bislithium salt. This can then be reacted with zirconiumtetrachloride to yieldethylenebis(2-tert-butyldimethylsiloxyindenyl)zirconium dichloride. Theracemic diastereomer of the latter is formed in great excess and iseasily separated from the meso isomer by fractional crystallization.Catalytic hydrogenation of race micethylenebis(2-tert-butyldimethylsiloxyindenyl)zirconium dichlorideyields the corresponding tetrahydroindenyl complex. The reaction takesplace according to the following reaction scheme (V):

In the reactions above butyllithium may be replaced as describedearlier. Zirconium tetrachloride can be replaced with titaniumtetrachloride or hafiiium tetrachloride to give the correspondingtitanium and hafnium complexes.

According to still another embodiment of the invention2-t-hexyldimethylsiloxyindene is reacted first with butyllithium andthen with dibromoethane to formbis(2-t-hexyldimethylsiloxyindenyl)ethane. This compound can be reactedwith two equivalents of butyllithium which gives the correspondingbislithium salt. This can then be reacted with zirconium tetrachlorideto yield ethylenebis(2-t-hexyldimethylsiloxyindenyl)zirconiumdichloride. The racemic diastereomer of the latter is formed in greatexcess and is easily separated from the meso isomer by fractionalcrystallization. The reaction takes place according to the followingreaction scheme (VI):

In the reactions above butyllithium may be replaced as describedearlier. Zirconium tetrachloride can be replaced with titaniumtetrachloride or hafiium tetrachloride to give the correspondingtitanium and hafnium complexes. Hydrogenation ofethylenebis(2-t-hexyldimethylsiloxyindenyl)zirconium dichloride yieldsthe corresponding tetrahydroindenyl complex.

Illustrative but non-limiting examples of the preferable compounds usedaccording to the invention are, among others, racemic and mesodimethylsilylbis(2-tert-butyldimethylsiloxyindenyl)zirconium dichloride,racemic and mesodiphenylsilylbis(2-tert-butyldimethylsiloxyindenyl)zirconium dichloride,racemic and mesodimethylsilylbis(2-t-hexyldimethylsiloxyindenyl)zirconium dichloride,racemic and mesodiphenylsilylbis(2-t-hexyldimethylsiloxyindenyl)zirconium dichloride,racemic and mesodimethylsilylbis(2-cyclohexyldimethylsiloxyindenyl)zirconium dichloride,racermic and mesodimethylsilylbis(2-cyclohexyldimethylsiloxyindenyl)zirconium dichloride,racemic and mesodimethylsilylbis(2-2-tert-butyldiphenylsiloxyindenyl)zirconiumdichloride, racemic and mesodiphenylsilylbis(2-tert-butyldiphenylsiloxyindenyl)zirconium dichloride,racemic and mesodimethylsilylbis(2-tert-butyldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racemic and mesodiphenylsilylbis(2-tert-butyldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racemic and mesodimethylsilylbis(2-t-hexldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racemic and mesodiphenylsilylbis(2-t-hexyldimethylsiloxy-4,5,6,7-tetranydroindenyl)zirconiumdichloride, racemic and mesodimethylsilylbis(2-cyclohexyldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racemic and mesodiphenylsilylbis(2-cyclohexyldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racermic and mesodimethylsilylbis(2-tert-butyldiphenylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racermic and mesodiphenylsilylbis(2-tert-butylphenylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, rac-ethylenebis(2-tert-butylnethylsiloxyindenyl)zirconiumdichloride, racemic and mesoethylenebis(2-t-hexyldimethylsiloxyindenyl)zirconium dichloride, racemicand meso ethylenebis(2-cyclohexyldimethylsiloxyindenyl)zirconiumdichloride, racemic and mesoethylenebis(2-tert-butyldiphenylsiloxyindenyl)zirconium dichloride,rac-ethylenebis(2-tert-butyldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racemic and mesoethylenebis(2-cyclohexvsldimethylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride, racernic and mesoethylenebis(2-tert-butyldiphenylsiloxy-4,5,6,7-tetrahydroindenyl)zirconiumdichloride and rac-ethylenebis(2-t-hexyldimethylsiloxyindenyl)zirconiumndichloride. Titanium or hafnium can be used instead of zirconium incorresponding complexes.

Particularly preferred bridged 3-(siloxy)indenyl and3-(siloxy)-4,5,6,7-tetrahydroindenyl metallocenes according to thepresent invention include: rac- andmeso-[ethylenebis(3-(tert-butyldimethylsiloxy)indenyl)]zirconiumdichloride; rac- andmeso-[dimethylsilylenebis(3-(tert-butyldimethylsiloxy)indenyl)]zirconiumdichloride; rac- andmeso-[ethylenebis(3-(t-hexyldimethylsiloxy)indenyl)]zirconiumdichloride; rac- andmeso-[dimethylsilylenebis(3-(t-hexyldimethylsiloxy)indenyl)]zirconiumdichloride; rac- andmeso-[ethylenebis(3-(tert-butyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]zirconiumdichloride; rac- andmeso-[dimethylsilylenebis(3-(tert-butyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]zirconiumdichloride; rac- andmeso-[ethylenebis(3-(t-hexyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]zirconiumdichloride and rac- andmeso-[dimethylsilylenebis(3-(t-hexyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]zirconiumdichloride; and the same hafnium compounds such as: rac- andmeso-[ethylenebis(3-(tert-butyldimethylsiloxy)indenyl)]hafniumdichloride; rac- andmeso-[dimethylsilylenebis(3-(tert-butyldimethylsiloxy)indenyl)]hafniumdichloride; rac- andmeso-[ethylenebis(3-(t-hexyldimethylsiloxy)indenyl)]hafnium dichloride;rac- andmeso-[dimethylsilylenebis(3-(t-hexyldimnethylsiloxy)indenyl)]hafiumdichloride; rac- andmeso-[ethylenebis(3-(tert-butyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]hafniumdichloride; rac- andmeso-[dimethylsilylenebis(3-(tert-butyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]hafniumdichloride; rac- andmeso-[ethylenebis(3-(t-hexyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]hafniumdichloride and rac- andmeso-[dimethylsilylenebis(3-(t-hexyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl)]hafnimndichloride; and the like.

When contacting said metallocene of the general formula (1) or (3), themetallocene is preferably dissolved in a chlorinated or non-chlorinatedC₃-C₁₀ hydrocarbon solvent and most preferably in an aromatichydrocarbon solvent such as toluene.

In the present process for the preparation of a homogeneous olefinpolymerization catalyst composition, the metallocene according toformula (1) or (3) is contacted with an aluminoxane of the generalformulas (2). Formulas (2) are general formulas including not onlylinear and cyclic compounds, but also aluminoxane compounds of cage andnet structures. See e.g. Harlan, et.al., J. Am Chem. Soc., 117, (1995)p. 6466, the aluminoxane structures of which are enclosed by referenceto disclose one embodiment of the invention.

The aluminoxane used in the process of the present invention ispreferably an aluminoxane (2), wherein said R′ is a C₃-C₁₀ alkyl group,more preferably an isopropyl, isobutyl, sec-butyl, tert-butyl, isoamyl,sec-amyl, tert-amyl isohexyl, sec-hexyl or tert-hexyl group. The mostpreferred aluminoxane of the formula (3) is preferably an aluminoxane inwhich 2≦p≦12, most preferably 4≦p≦8. A suitable aluminoxane of theformula (2) is hexa(isobutylaluminiumoxane). The aluminoxane accordingto the present invention can be prepared analogously to or by modifyinga variety of methods for preparing aluminoxane, non-limiting examples ofwhich are described in U.S. Pat. Nos. 4,665,208, 4,952,540, 5,091,352,5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827,5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,157,137, 5,103,031, EP-A-0561 476, EP-B1-0 279 586, EP-A-0 594 218 and WO 94/10180.

It is preferable to contact said metallocene of formula (1) or (3)previous to, immediately before, or at the beginning of the olefinpolymerization, with an aluminoxane of formula (2) dissolved or immersedin a chlorinated or unchlorinated hydrocarbon solvent such as hexane ortoluene. When contacting said metallocene of the formula (1) or (3) withsaid aluminoxane of the formula (2), the molar ratio between thealuminoxane aluminium metal and the metallocene transition metal in thecatalyst composition is preferably between 20 and 2000, more preferably50 and 1500 and most preferably between 100 and 1200. The concentrationof metallocene in the catalyst composition is preferably regulated tobetween 0.01 and 100 mmol/l, more preferably to between 0.1 and 50mmol/l, even more preferably to between 0.5 and 10 mmol/l, mostpreferably to between 1 and 5 mmol/l.

When preparing a supported olefin polymerization catalyst compositionaccording to the present invention, the contacting product between themetallocene of the general formula (1) or (3) and the aluminoxane of thegeneral formula (2) can be subjected to a prepolymerization with atleast one olefin such as propylene and/or ethylene. The prepolymerizateis then recovered as said supported olefin polymerization catalystcomposition. The process may also include a step of solidification (e.g.by precipitation, evaporation, crystallization) of said catalyst,whereby a homogeneous solid is obtained.

In addition to the above described process for the preparation of ahomogeneous olefin polymerization catalyst composition, the presentinvention also relates to a homogeneous olefin polymerization catalystcomposition which has been prepared according to said described process.The invention also relates to a process for polymerizing at least oneolefin by polymerizing in the presence of said homogeneous olefinpolymerization catalyst or a catalyst prepared according to the abovedescribed process. In the polymerization (homopolymerization orcopolymerization) olefin monomers, such as ethylene, propylene,1-butylene, isobutylene, 4-methyl-1-pentene, 3-methyl-1-butene,4,4-dimethyl-1-pentene, vinylcyclohexene, 1-decene and their comonomers,can be used. Dienes and cyclic olefins can also be homo- orcopolymerized. These α-olefins and other monomers can be used both inthe polymerization and prepolymerization using the claimed supportedolefin polymerization catalyst composition.

The polymerization can be a homopolymenization or a copolymerization andit can take place in the gas, slurry or a solution phase. The claimedcatalyst composition can also be used in high pressure processes. Saidα-olefins can be polymerized together with higher α-olefins in order tomodify the properties of the final product. Such higher olefins are1-hexene, 1-octene, 1-decene, etc.

In the following, the present invention is illustrated by non-limitedexamples.

COMPARATIVE EXAMPLES Comparative Example 1

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 34 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 20 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.5 μmol/ml (1.7 mg/ml). To form the metallocene/MAO(methyl aluminoxane) complex, 0.25 ml of said metallocene compoundsolution was added into 10 ml of additional toluene containing 0.11 mlof 30 w-% MAO. The final Al/Zr-ratio was 500.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.4 bar. Into the reactor, 10 ml of previouslyprepared complex solution was fed. The total amount of metallocenecompound was 0.63 μmol (0.44 mg) and the Al/Zr-ratio was 500. After 30min of polymerization the reaction was stopped by closing the ethylenefeed and releasing the overpressure from the reactor. The yield ofpolymer was 73 g giving a total catalyst activity of 2540 kgPE/g*Zr*h.

Comparative example 2

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 34 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 20 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.5 μmol/ml (1.7 mg/ml). To form the metallocene/MAOcomplex, 1.0 ml of metallocene compound solution was added into 10 ml ofadditional toluene containing 0.17 ml of 30 w-% MAO. The finalAl/Zr-ratio was 200.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.4 bar. Into the reactor, 10 ml of previouslyprepared complex solution was fed. The total amount of metallocenecompound was 2.5 μmol (1.7 mg) and the Al/Zr-ratio was 200. After 30 minthe polymerization reaction was stopped by closing the ethylene feed andreleasfin the overpressure from the reactor. The yield of polymer was120 g giving a total catalyst actilvity of 1036 kgPE/g*Zr*h.

Comparative Example 3

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 34 mg, ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 10 ml moisture and oxygen free toluene. The fmnal solution had aconcentration of 2.5 μmol/ml (1.7 mg/ml). To form a metallocene/MAOcomplex, 0.25 ml of the metallocene compound solution was added into 10ml of additional toluene containing 0.02 ml of 30 w-% MAO. The finalAl/Zr-ratio was 100.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.1 bar. Into the reactor, 10 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 0.63 μmmol (0.44 mg) and the Al/Zr-ratio was 100. After 30min, the polymerization reaction was stopped by closing the ethylenefeed and releasing the overpressure from the reactor. The yield ofpolymer was 12 g giving a total catalyst activity of 406 kgPE/g*Zr*h.

Comparative Example 4

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 20.9 mg ofrac-ethylene-bis(indenyl)zirconiumdichloride into 20 ml moisture andoxygen free toluene. The final solution had a concentration of 2.5μmol/ml (1.045 mg/ml). To form a metallocene/MAO complex, 1.0 ml of themetallocene compound solution was added into 10 ml of additional toluenecontaining 0.43 ml of 30 w-% MAO. The final Al/Zr-ratio was 500.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.6 bar. Into the reactor 2.5 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 0.63 μmol (0.26 mg) and the Al/Zr-ratio was 500. After 30min of polymerization the reaction wvas stopped by closing the ethylenefeed and releasing the overpressure from the reactor. The yield ofpolymer was 25 g giving a total catalyst activity of 842 kgPE/g*Zr*h.

Comparative Example 5

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 20.9 mg ofrac-ethylene-bis(indenyl)zirconiumdichloride into 20 ml moisture andoxygen free toluene. The final solution had a concentration of 2.5μmol/ml (1.045 mg/ml). To form a metallocene/MAO complex, 1.0 ml of themetallocene compound solution was added into 10 ml of additional toluenecontaining 0.17 ml of 30 w-% MAO. The final Al/Zr-ratio was 200.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.6 bar. Into the reactor, 2.5 ml of previouslyprepared complex solution was fed. The total amount of metallocenecompound was 0.63 μmnol (0.26 mg) and the Al/Zr-ratio was 200. After 30min the polymerization reaction was stopped by closing the ethylene feedand releasing the overpressure from the reactor. The yield of polymerwas 27 g giving a total catalyst activity of 910 kgPE/g*Zr*h.

Comparative Example 6

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 20.9 mg ofrac-ethylene-bis(indenyl)zirconimumdichloride into 20 ml moisture andoxygen free toluene. The final solution had a concentration of 2.5μmol/ml (1.045 mg/ml). To form the metallocene/MAO complex, 1.0 ml ofthe metallocene compound solution was added into 10 ml of additionaltoluene containing 0.09 ml of 30 w-% MAO. The final Al/Zr-ratio was 100.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.6 bar. Into the reactor, 2.5 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 0.63 μmnol (0.26 mg) and the Al/Zr-ratio was 100. After 30min, the polymerization reaction was stopped by closing the ethylenefeed and releasing the overpressure from the reactor. The yield ofpolymer was 9 g giving a total catalyst activity of 302 kgPE/g*Zr*h.

Example 7′

Preparation of the Complex Solution

A complex solution of metallocene was prepared by adding 20 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 11.5 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.54 μmol/ml (1.74 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.2 bar. Into the reactor, 1 ml of the previouslyprepared complex solution was fed together with 1.1 ml of MMAO-4. MMAO-4is methyl aluminoxane containing 30% by weight of isobutyl groups. Thetotal amount of metallocene compound was 2.54 μmol (1.74 mg) and theAl/Zr-ratio was 1000. After 12 min, the polymerization vessel was fullof polymer and the reaction was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was110 g giving a total catalyst activity of 2357 kgPE/g*Zr*h.

Comparative Example 8

Preparation of the Metallocene Solution

A solution of metallocene was prepared by adding 10 mg(1.2)-ethylene-bis(indenyl)zirconiumdichloride into 10 ml moisture andoxygen free toluene. The final solution had a concentration of 2.75μmol/ml (1 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into the reactor, 1.15 ml of the previouslyprepared complex solution and 2.64 ml HIBAO (HIBAO=hexaisobutylaluminoxane) 20% in hexane was added. The Al/Zr-ratio was 1055. A metalcylinder was tightened to the reactor. The volume of isobutane was 1.8liters. Half of the isobutane was fed into the reactor beforehand. Theother half of the isobutane was used to wash the catalyst from the metalcylinder into the reactor when streaming throug the cylinder. Thereaction time was 60 minutes. After that the ethylene feed valve wasclosed and the over pressure was released from the reactor. The yield ofpolymer was 18 g and the total catalyst activity was 64 kgPE/g*Zr*h.

Comparative Example 9

Preparation of the Metallocene Solution

As in comparative example 8

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into the reactor, 1.15 ml of the previouslyprepared complex solution and 1.32 ml of HIBAO 20% in hexane was added.The Al/Zr-ratio was 527. A metal cylinder was tightened to the reactor.The volume of isobutane was 1.8 liters. Half of the isobutane was fedinto the reactor beforehand. The other half of isobutane was used towash the catalyst from the metal cylinder into the reactor whenstreaming through the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 1 g and the totalcatalyst activity was 8 kgPE/g*Zr*h.

Comparative Example 10

Preparation of the Metallocene Solution

As in comparative example 8

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into the reactor, 1.15 ml of the previouslyprepared complex solution and 0.66 ml HIBAO 20% in hexane was added. TheAl/Zr-ratio was 264. A metal cylinder was tightened to the reactor. Thevolume of isobutane was 1.8 liters. Half of the isobutane was fed intothe reactor beforehand. The other half of the isobutane was used to washthe catalyst from the metal cylinder into the reactor when streamingthroug the cylinder. The reaction time was 60 minutes. After that theethylene feed valve was closed and the overpressure was released fromthe reactor. The yield of polymer was 3 g and the total catalyst wasactivity 24 kgPE/g*Zr*h.

Comparative Example 11

Preparation of the Metallocene Solution

A solution of metallocene was prepared by adding 10 mg ofn-butyldicyclopentadienylzirconium dichloride into 10 ml moisture andoxygen free toluene. The final solution had a conceration 2.47 μmol/ml(1 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.5 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 2.26 ml of 20% HIBAO in cyclohexane wasfed. The Al/Zr-ratio was 1006. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 13 g and the totalcatalyst activity was 106 kgPE/g*Zr*h.

Comparative Example 12

Preparation of the Metallocene Solution

As in comparative example 11

Test Polymerization

A test polymenrzation was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.6 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 1.13 ml of 20% HIBAO in hexane was fed.The Al/Zr-ratio was 503. A metal cylinder was tightened to the reactor.The volume of isobutane was 1.8 liters. Half of the isobutane was fedinto the reactor beforehand. The other half of the isobutane was used towash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 6 g and the totalcatalyst activity was 53 kgPE/g*Zr*h.

Comparative Example 13

Preparation of the Metallocene Solution

As in comparative example 11

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.5 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 0.57 ml of HIBAO 20% in cyclohexane wasfed. The Al/Zr-ratio was 254. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 6 g and the totalcatalyst activity was 53 kgPE/g*Zr*h.

Comparative Example 14

Preparation of the Metallocene Solution

As in comparative example 11

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 1.3 ml TIBAO (TIBAO=tetraisobutylaluminoxane) 30% in cyclohexane was fed. The Al/Zr-ratio was 897. Ametal cylinder was tightened to the reactor. The volume of isobutane was1.8 liters. Half of the isobutane was fed into the reactor beforehand.The other half of the isobutane was used to wash the catalyst from themetal cylinder into the reactor when streaming throug the cylinder. Thereaction time was 60 minutes. After that the ethylene feed valve wasclosed and the overpressure was released from the reactor. The yield ofpolymer was 3 g and the total catalyst activity was 25 kgPE/g*Zr*h.

Comparative Example 15

Preparation of the Metallocene Solution

As in comparative example 11

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 0.5 ml of 30% TIBAO in cyclohexane wasfed. The Al/Zr-ratio was 345. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 3 g and the totalcatalyst activity was 25 kgPE/g*Zr*h.

EXAMPLES Example 1

Preparation of the Complex Solution

A complex solution of metallocene/HIBAO was prepared by adding 20 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 11.5 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.54 μmol/ml (1.74 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.2 bar. Into the reactor. 1 ml of the previouslyprepared complex solution was fed together with 2 ml of HIBAO. The totalamount of metallocene compound was 2.54 μmol (1.74 mg) and theAl/Zr-ratio was 1000. After 20 min, the polymerization was stopped byclosing the ethylene feed and releasing the overpressure from thereactor. The yield of polymer was 60 g giving a total catalyst activityof 777 kgPE/g*Zr*h.

Example 2

Preparation of the Complex Solution

As in example 1

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.2 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed together with 1 ml of HIBAO. The totalamount of metallocene compound was 2.54 μmol (1.74 mg) and theAl/Zr-ratio was 500. After 30 min the polymerization reaction wasstopped by closing the ethylene feed and releasing the overpressure fromthe reactor. The yield of polymer was 62 g giving a total catalystactivity of 535 kgPE/g*Zr*h.

Example 3 (repeated example 2)

Preparation of the Complex Solution

A complex solution was prepared in situ by adding 10 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloridedirectly into 6 ml of HIBAO solution. The final solution had aconcentration of 2.4 μmol/ml (1.67 mg/ml) and the Al/Zr-ratio is 500.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.4 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 2.4 pmol (1.65 mg) and the Al/Zr-ratio was 500. After 28min, the polymerization was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was 63g giving a total catalyst activity of 562 kgPE/g*Zr*h.

Example 4

Preparation of the Metallocene Solution

A solution of the metallocene was prepared by adding 24 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 12 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.95 μmol/ml (2.0 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.3 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 1.0 ml of 20% HIBAO in hexane was added.The Al/Zr-ratio was 373. A metal cylinder was tightened to the reactor.The volume of isobutane was 1.8 liters. Half of the isobutane was fedinto the reactor beforehand. The other half of the isobutane was used towash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the over pressure wasreleased from the reactor. The yield of polymer was 67 g and the totalcatalyst activity was 494 kgPE/g*Zr*h.

Example 5

Preparation of the Complex Solution

A complex solution was prepared in situ by adding 10 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloridedirectly into 3 ml of a HIBAO solution. The final solution had aconcentration of 2.4 μmol/ml (1.67 mg/ml) and the Al/Zr-ratio was 250.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.2 bar. Into the reactor, 2.0 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 4.8 μmol (3.3 mg) and Al/Zr-ratio was 250. After 30 min,the polymerization was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was 40g and the total catalyst activity was 180 kgPE/g*Zr*h.

Example 6

Preparation of the Complex Solution

A complex solution was prepared in situ by adding 10 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloridedirectly into 3 ml of a HIBAO solution. The final solution had aconcentration of 2.4 μmol/ml (1.67 mg/ml) and the Al/Zr-ratio was 250.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.2 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 2.4 μmol (1.65 mg) and Al/Zr-ratio was 250. After 30 min,the polymerization was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was 20g and the total catalyst activity was 175 kgPE/g*Zr*h.

Example 7

Preparation of the Metallocene Solution

A solution of the metallocene was prepared by adding 15 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 10 ml moisture and oxygen free toluene. The final solution had aconcentration of 2.35 μmol/ml (1.5 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.5 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 1.0 ml of 20% HIBAO in hexane was added.The Al/Zr-ratio was 468. A metal cylinder was tightened to the reactor.The volume of isobutane was 1.8 liters. Half of the isobutane was fedinto the reactor beforehand. The other half of the isobutane was used towash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the over pressure wasreleased from the reactor. The yield of polymer was 118 g and the totalcatalyst activity was 1100 kgPE/g*Zr*h.

Example 8

Preparation of the Metallocene Solution

As in example 7

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.2 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 0.54 ml of 20% HIBAO in hexane was added.The Al/Zr-ratio was 252. A metal cylinder was tightened to the reactor.The volume of isobutane was 1.8 liters. Half of the isobutane was fedinto the reactor beforehand. The other half of isobutane was used towash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the over pressure wasreleased from the reactor. The yield of polymer was 88 g and the totalcatalyst activity was 704 kgPE/g*Zr*h.

Example 9

Preparation of the Complex Solution

A complex solution wvas prepared in situ by adding 5 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloridedirectly into 6.0 ml of a TIBAO solution. The final solution had aconcentration of 1.2 μmol/ml (0.83 mg/ml) and the Al/Zr-ratio was 1000.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.3 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed. The total amount of metailocenecompound was 1.2 μmol (0,83 mg) and the Al/Zr-ratio was 1000. After 40min, the polymerization reaction was stopped by closing the ethylenefeed and releasing the overpressure from the reactor. The yield ofpolymer was 22 g giving a total catalyst activity 296 kgPE/g*Zr*h.

Example 10

Preparation of the Complex Solution

As in example 1

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 9.2 bar. Into the reactor, 1 ml of the previouslyprepared complex solution was fed together with 1 ml of TIBAO. The totalamount of metallocene compound was 2.54 μmol (1.74 mg/ml) and theAl/Zr-ratio was 500. After 60 min, the polymerization was stopped byclosing the ethylene feed and releasing the overpressure from thereactor. The yield of polymer was 25 g giving a total catalyst activity110 kgPE/g*Zr*h.

Example 11

Preparation of the Complex Solution

A complex solution was prepared in situ by adding 20 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloeneadenyl)zironiumdichloridedirectly into 12.0 ml of a TIBAO solution. The final solution had aconcentration of 2.54 μmol/ml (1.74 mg/ml) and the Al/Zr-ratio was 500.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.1 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 2.4 μmol (1.67 mg) and the Al/Zr-ratio was 500. After 30min, the polymerization was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was 12g giving a total catalyst activity 107 kgPE/g*Zr*h.

Example 12

Preparation of the Complex Solution

A complex solution was prepared in situ by adding 10 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloridedirectly into 12.0 ml of a TIBAO solution. The final solution had aconcentration of 4.8 μmol/ml (3.3 mg/ml) and the Al/Zr-ratio was 250.

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8 bar. Into the reactor, 0.5 ml of the previouslyprepared complex solution was fed. The total amount of metallocenecompound was 2.4 μmol (1.67 mg) and the Al/Zr-ratio was 250. After 60min, the polymerization was stopped by closing the ethylene feed andreleasing the overpressure from the reactor. The yield of polymer was 8g giving a total catalyst activity 36 kgPE/g*Zr*h.

Example 13

Preparation of the Metallocene Solution

As in example 7

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.2 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 1.23 ml of 30% TIBAO in cyclohexane wasadded. The Al/Zr-ratio was 892. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming through the cylinder. The reaction time was 30 minutes. Afterthat the ethylene feed valve was closed and the over pressure wasreleased from the reactor. The yield of polymer was 60 g and the totalcatalyst activity was 560 kgPE/g*Zr*h.

Example 14

Preparation of the Metallocene Solution

As in example 7

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.2 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution and 0.65 ml of 30% of TIBAO in cyclohexane wasadded. The Al/Zr-ratio was 500. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 30 minutes. Afterthat the ethylene feed valve was closed and the over pressure wasreleased from the reactor. The yield of polymer was 26 g and the totalcatalyst activity was 260 kgPE/g*Zr*h.

Example 15

Preparation of the Metallocene Solution

A solution of metallocene was prepared by adding 16 mg ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 10 ml of moisture and oxygen free toluene. The final solution had aconcentration of 2.47 μmol/ml (1.6 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.4 bar. Into a metal cylinder, 1.0 ml of thepreviously prepared complex solution and 1.0 ml of 20% HIBAO in hexanewas fed. The Al/Zr-ratio was 500. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenstreaming throug the cylinder. The reaction time was 60 minutes. Afterthat the ethylene feed valve was closed and the overpressure wasreleased from the reactor. The yield of polymer was 78 g and the totalcatalyst activity was 692 kgPE/g*Zr*h.

Example 16

Preparation of the Complex Solution

As in example 1

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 8.7 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed together with 1.2 ml of EAO(EAO=ethylaluninoxane). The total amount of metallocene compound was2.54 μimol (1.74 mg) and the Al/Zr-ratio was 1000. The reaction time was60 minutes. After 60 min, the polymerization was stopped by closing theethylene feed and releasing the overpressure from the reactor. The yieldof polymer was 40 g giving a total catalyst activity 174 kgPE/g*Zr*h.

Example 17

Preparation of the Complex Solution

As in example 1

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inn-pentane at 70° C. The ethylene partial pressure was 5 bar and thetotal pressure was 9 bar. Into the reactor, 1.0 ml of the previouslyprepared complex solution was fed together with 0.6 ml of EAO. The totalamount of metallocene compound was 2.54 μmol (1.74 mg) and theAl/Zr-ratio was 500. After 60 min, the polymerization was stopped byclosing the ethylene feed and releasing the overpressure from thereactor. The yield of polymer was 35 g giving a total catalyst activity153 kgPE/g*Zr*h.

Example 18

Preparation of the Metallocene Solution

A solution of the metallocene was prepared by adding 17 mg ofrac-ethylene-bis(3-tert-butyldimethylsiloxyindenyl)zirconiumdichlorideinto 10 ml of moisture and oxygen free toluene. The final solution had aconcentration of 2.5 μmol/ml (1.7 mg/ml).

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.5 bar. Into a metal cylinder, 1.0 ml of thepreviously prepared complex solution and 1.0 ml of 20% HIBAO in hexanewas fed. The Al/Zr-ratio was 500. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenpassing the cylinder. The reaction time was 60 minutes. After that theethylene feed valve was closed and the overpressure was released fromthe reactor. The yield of polymer was 126 g and the total catalystactivity was 552 kgPE/g*Zr*h.

Example 19

Preparation of the Metallocene Solution

As in example 18

Test Polymerization

A test polymerization was carried out in a 3-liter Büchi autoclave inisobutane at 71° C. The ethylene partial pressure was 5 bar and thetotal pressure was 15.8 bar. Into a metal cylinder, 1.0 ml of thepreviously prepared complex solution and 0.5 ml of 20% HIBAO in hexanewas fed. The Al/Zr-ratio was 250. A metal cylinder was tightened to thereactor. The volume of isobutane was 1.8 liters. Half of the isobutanewas fed into the reactor beforehand. The other half of the isobutane wasused to wash the catalyst from the metal cylinder into the reactor whenpassing the cylinder. The reaction time was 60 minutes. After that theethylene feed valve was closed and the overpressure was released fromthe reactor. The yield of polymer was 90 g and the total catalystactivity was 395 kgPE/g*Zr*h.

TABLE 1 Conditions in homopolymerization are P_(C2) = 5 bar, temperature70° C. in pentane, compound 1 =rac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichlo-ride, compound 2 =rac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconium- dimethylcompound 3 = rac-ethylene-bis(2-tert-butyldimethylsiloxytetrahydroinde-nyl)zirconiumdichloride, compound 4 =rac-ethylene-bis(3-tert-butyldimethylsiloxy-indenyl)zirconiumdichloride, REF. Compound 1 =ethylene-bis(indenyl)zirconium- dichloride, REF. Compound 2 =n-butylcyclopentadienyl zirconiumdichloride MAO = 30 w-% methylalumoxanein toluene, HIBAO = heksaisobutylalumoxane, TIBAO =tetraisobutylalumoxane, EAO = ethylalumoxane, MMAO = modifiedmetylalumoxane containing 10% isobutyl groups. Activity time Amount ofYield kgPE/g · Metallocene Cocatalyst Al/Zr min comp. g Zr · h M_(V) DExample Compound 1 MAO 500 30 0.65 μmol 73 2540 114000 2.8 Comparativeexample 1 ″ ″ 200 30 2.54 μmol 120 1036 238000 4.0 Comparative example 2″ ″ 100 30 0.63 μmol 12 406 Comparative example 3 REF. ″ 500 30 0.65μmol 25 842 124000 2.8 Comparative Compound 1 example 4 ″ ″ 200 30 0.65μmol 27 910 128000 3.4 Comparative example 5 ″ ″ 100 30 0.65 μmol 9 302101000 2.9 Comparative example 6 Compound 1 MMAO-4 1000 12 2.54 μmol 1102357 Comparative example 7 REF. HIBAO 1000 60 2.75 μmol 18 64Comparative Compound 1 example 8 ″ ″ 500 60 2.75 μmol 1 8 Comparativeexample 9 ″ ″ 250 60 2.75 μmol 3 24 Comparative example 10 Compound 1HIBAO 1000 20 2.54 μmol 60 777 Example 1 ″ ″ 500 30 2.54 μmol 62 535298000 6.9 Example 2 ″ ″ 500 28  2.4 μmol 63 562 Example 3 ″ ″ 370 302.95 μmol 67 494 Example 4 ″ ″ 250 30  4.8 μmol 40 180 Example 5 ″ ″ 25030  2.4 μmol 20 175 Example 6 Compound 2 HIBAO 470 30 2.35 μmol 118 1100Example 7 ″ ″ 250 30 2.35 μmol 88 704 Example 8 Compound 4 HIBAO 500 602.50 μmol 126 552 Example 18 ″ ″ 250 60 ″ 90 395 Example 19 REF. HIBAO1000 60 2.47 μmol 13 106 Comparative compound 2 example 11 ″ ″ 500 60 ″6 53 Comparative example 12 ″ ″ 250 60 ″ 6 53 Comparative example 13Compound 1 TIBAO 1000 40  1.2 μmol 22 296 Example 9 ″ ″ 500 60 2.54 μmol25 110 Example 10 ″ ″ 500 30  2.4 μmol 12 107 Example 11 ″ ″ 250 60 ″ 836 Example 12 Compound 2 TIBAO 898 30 2.35 μmol 60 560 Example 13 ″ ″500 30 ″ 26 260 Example 14 Compound 3 HIBAO 500 60 2.47 μmol 78 690Example 15 REF. TIBAO 890 60 2.47 μmol 3 25 Comparative Compound 2example 14 ″ ″ 345 60 2.47 μmol 3 25 Comparative example 15 Compound 1EAO 1000 60 2.54 μmol 40 175 116000 3.5 Example 16 ″ ″ 500 60 ″ 35 153159000 4.5 Example 17 ″ HIBAO 500 60 — 126 552 Example 18 ″ ″ 250 60 —90 395 Example 19

rac-ethylene-bis(2-tert-butylmethylsiloxyidenyl)zirconiumdichloride(compound 1)

rac-ethylene-bis(2-tert-butylmethylsiloxyindenyl)zirconiumdimethyl(compound 2)

rac-ethylene-bis(2-tert-butyhmethylsiloxytetrahydroindenyl)zirconiumdichloride(compound 3)

rac-ethylene-bis(2-tert-butylmethylsiloxyindenyl)zirconiumdichloride(compound 4)

REF. compound 1=ethylene-bis(indenyl)zirconiumdichloride

REF. compound 2=n-butylcyclopentadienylzirconiuidlchloride

Some conclusions from the examples of this application

1. General Behaviour ofrac-ethylene-bis(2-tert-butyldimethylsiloxyindenyl)zirconiumdichloride/MAOcomplex

Comparative examples 1, 2, 3 illustrate the genereal behaviour of siloxysubstituted cyclopentadienyl compounds when activated by conventionalmethylaluminoxane with different Al/Zr-ratios.

2. General Behaviour of ethylene-bis(indenyl)zirconiumdichloride/MAOComplex

Comparative examples 4, 5, 6 illustrate the general polymerizationbehaviour of non-siloxysubstituted cyclopentadienyl compounds when MAOis used with different Al/Zr-ratios.

3. Polymerization with Sligthly Modified MAO

Comparative example 7 indicates that addition of isobutyl groups intoMAO does not affect the activity of siloxy substituted compound. Thisexperiment should be compared to comparative example 1, where pure MAOwas used. No significant change in catalyst performance can be seen.

4. Polymerization of Siloxy Substituated Compounds withHexaisobutylaluminoxane (=HIBAO)

Examples 1-6 illustrate the general behaviour of new non-MAO basedcoactivator system with siloxy substituted compounds. Al/Zr-ratio willclearly affect onto catalyst activity. Example 7 reflects the use ofmetallocene compounds having methyls at the metal.

5. Effect of Precontact of Siloxy Substituted Metallocene and HIBAO

In example 2 metallocene and HIBAO were fed separately into reactor. Inexample 3, metallocene and HIBAO were mixed before going into thereactor. No clear difference can be seen in activity. Conclusion:metallocene and coactivator can be fed together or separately into thereactor.

6. Effect of Concentration

Examples 5 and 6 indicate that concentration of metallocene compound canbe varied quite much without affecting the catalyst activity.

7. Polymerization of Siloxy Substituted Compounds withTetraisobutylaluminoxane (=TIBAO)

Examples 9, 10, 11, 12 will discribe the use of tetraisobutylaluminoxaneas a coactivator with siloxy substituted metallocene compounds.

8. Polymerization of Siloxy Substituted Compounds with Ethylaluminoxane(=EAO)

Examples 16, 17 discribe the use of ethylaluminoxane as a coactivatorwith siloxy substituted metallocene compounds.

9. Comparison of Siloxy Substituted Compounds and Corresponding NonSubstituted Compound with HIBAO as a Coactivator.

Examples 1, 2, 3 and 5 can be compared directly with comparativeexamples 8, 9, 10. According to these examples it is evident that siloxysubstitution gives huge enhancement in catalyst activity with HIBAO. Theactivity increase is more than 10 fold.

10. Comparison of Methylated Siloxy Substituted Compounds andCorresponding Non Methylated Compound with HIBAO and TIBAO as aCoactivator.

Example 5 and 8 present the affect of methylation of the siloxysubstituted compound. The activity increase is 4 times when HIBAO isused as a coactivator. In examples 9 and 13 coactivator is TIBAO andactivity is 2 times higher with methylene substituted compound. Bymethylation is meant that in stead of chlorines, methyls are attached tothe metal of the metallocene.

11. Position of Siloxy Substituent

Examples 5 and 18 describe the affect of position of substituent. Bychanging the place of substituent from the 2 position to the 3 positionthe activity increased 2,5 times.

What is claimed is:
 1. An olefin polymerization catalyst compositioncomprising a metallocene and an aluminoxane or a reaction productthereof, wherein said metallocene is of formula (1).(CpY_(q))_(m)MX_(n)Z_(o)  (1) wherein Cp having the same or differentstructure is one of a mono- or polysubstituted, fused or non-fused,homo-, iso-, or heterocyclic cyclopentadienyl ligand, indenyl ligand,tetrahydroindenyl ligand, fluorenyl ligand, or octahydrofluorenylligand, Y or each same or different Y is a substituent at thecyclopentadienyl ring of said Cp ligand and is one of an —OR, —SR, —NR₂,—C(H or R)═, or —PR₂ radical, R or each same or different R being one ofa substituted or unsubstituted C₁-C₁₆ hydrocarbyl group, a tertiarysubstituted-C₁-C₈ hydrocarbylsilyl group, a tertiary substituted-C₁-C₈hydrocarbyloxy silyl group, a mixed C₁-C₈ hydrocarbyl and C₁-C₈hydrocarbyloxy silyl group, a tertiary substituted-C₁-C₈ hydrocarbylgermyl group, a tertiary substituted-C₁-C₈ hydrocarbyloxy germyl groupor a mixed C₁-C₈ hydrocarbyl and C₁-C₈ hydrocarbyloxy germyl group; M isa transition metal of Group 4 of the IUPAC Periodic Table and bound tothe ligand or ligands Cp in at least an η⁵ bonding mode; X or each sameor different X is bound to M and is one of a hydrogen, a halogen, asubstituted or unsubstituted C₁-C₈ hydrocarbyl group, a C₁-C₈ O—, S—, N—or P— hydrocarbylheteroatom group or a tertiary substituted-C₁-C₈hydrocarbyl silyl group or two X form together with M a C₄-C₂₀metallocyclic ring structure; Z is a bridge atom or group between two Cpligands or between one Cp ligand and the transition metal M; q is, whenCp is unbridged, 0-5 for Cp=cyclopentadienyl, 0-3 for Cp=indenyl ortetrahydroindenyl and 0-1 for Cp=fluorenyl or octahydrofluorenyl, or qis, when Cp is bridged, 0-4 for Cp=cyclopentadienyl, 0-2 for Cp=indenylor tetrahydroindenyl and 0 or Cp=fluorenyl or octahydrofluorenyl; m is 1or 2; the total number of Y substituents ≧1; o is 0 or 1; and n is4-m-o, except when there is a bridge Z between two Cp ligands, in whichcase n is 4-m, and in that said aluminoxane contains alkyl groupscontaining at least two carbon atoms.
 2. A composition as claimed inclaim 1, wherein said composition comprises the reaction product of saidaluminoxane and said metallocene.
 3. A composition as claimed in claim1, wherein said aluminoxane contains alkyl groups containing from 2 to10 carbon atoms.
 4. A composition as claimed in any one of claims 1 to3, wherein said composition further comprises a porous particulatecarrier material.
 5. A composition as claimed in claim 1, wherein saidmetallocene is of formula (3)

wherein each of the Y₁'s and Y₂'s is the same or different and is one ofa hydrogen atom, a halogen atom, an acyl group, an acyloxy group, asubstituted or unsubstituted C₁-C₁₀ hydrocarbyl group, an —OR, —SR, —NR,—C(H or R)═, or —PR₂ radical, R being one of a C₁-C₁₆ hydrocarbyl groupor a tertiary substituted-C₁-C₈ hydrocarbylsilyl group, provided that atleast one of the Y₁'s and Y₂'s is one of said —OR, —SR, —NR, —C(H orR)═, or —PR₂ radicals; Z is a bivalent atom or group having at least onechain atom which is one of a carbon, silicon, oxygen, sulphur, nitrogen,or phosphorus atom; each R″ is the same or different ad is one of ahydrogen atom, a halogen atom, a C₁-C₁₀ hydrocarbyl group, or ringconstituent or a C₁-C₁₀ hydrocarbyloxy group, M is one of Ti, Zr, or Hf;and X₁ and X₂ are the same or different and are one of a halogen atomand a C₁-C₈ hydrocarbyl group.
 6. A process for the preparation of anolefin polymerization catalyst, comprising contacting a) a metalloceneof the general formula (1): (CpY_(q))_(m)MX_(n)Z_(o)  (1)  wherein Cphaving the same or different structure is one of a mono- orpolysubstituted, fused or non-fused, homo-, iso-, or heterocycliccyclopentadienyl ligand, indenyl ligand, tetrahydroindenyl ligand,fluorenyl ligand, or octahydrofluorenyl ligand, Y or each same ordifferent Y is a substituent at the cyclopentadienyl ring of said Cpligand and is one of an —OR, —SR, —NR₂, —C(H or R)═, or —PR₂ radical, Ror each same or different R being one of a substituted or unsubstitutedC₁-C₁₆ hydrocarbyl group, a tertiary substituted-C₁-C₈ hydrocarbylsilylgroup, a tertiary substituted-C₁-C₈ hydrocarbyloxy silyl group, a mixedC₁-C₈ hydrocarbyl and C₁-C₈ hydrocarbyloxy silyl group, a tertiarysubstituted-C₁-C₈ hydrocarbyl germyl group, a tertiary substituted-C₁-C₈hydrocarbyloxy germyl group or a mixed C₁-C₈ hydrocarbyl and C₁-C₈hydrocarbyloxy germyl group; M is a transition metal of Group 4 of theIUPAC Periodic Table and bound to the ligand or ligands Cp in at leastan η5 bonding mode; X or each same or different X is bound to M and isone of a hydrogen, a halogen, a substituted or unsubstituted C₁-C₈hydrocarbyl group, a C₁-C₈ O—, S—, N— or P— hydrocarbylheteroatom groupor a tertiary substituted-C₁-C₈ hydrocarbyl silyl group or two X formtogether with M a C₄-C₂₀ metallocyclic ring structure; Z is a bridgeatom or group between two Cp ligands or between one Cp ligand and thetransition metal M; q is, when Cp is unbridged, 0-5 forCp=cyclopentadienyl, 0-3 for Cp=indenyl or tetrahydroindenyl and 0-1 forCp=fluorenyl or octahydrofluorenyl, or q is, when Cp is bridged, 0-4 forCp=cyclopentadienyl, 0-2 for Cp=indenyl or tetrahydroindenyl and 0 orCp=fluorenyl or octahydrofluorenyl; m is 1 or 2; the total number of Ysubstituents ≧1; o is 0 or 1; and n is 4-m-o, except when there is abridge Z between two Cp ligands, in which case n is 4-m, and b) analuminoxane of one of the following formulas (2):

 wherein each R′ is the same or different and is a C₂-C₁₀ alkyl group;and p is an integer between 1 and 40, and c) an organic solvent whichdissolves said metallocene and said aluminoxane or a reaction product ofthem, and recovering said homogeneous olefin polymerization catalystcomposition.
 7. The process according to claim 6, wherein Y in formula(1) is a —OR radical.
 8. The process according to claim 6, wherein thegroup R of the radical —OR, —SR, —NR₂, —CR═ or —PR₂ is a tertiarysubstituted C₁-C₈ hydrocarbyl silyl group.
 9. The process according toclaim 8, wherein R is a tertiary substituted-C₁-C₈ hydrocarbyl silylgroup capable of π interaction with said O, S, N, or P atoms of Y,preferably a tertiary substituted-C₁-C₈ alkyl silyl group, wherein atleast one of the C₁-C₈ alkyls is a branched C₃-C₈ alkyl preferablyisopropyl, isobutyl, sec-butyl, tert-butyl, isoamyl, sec-amyl, ortert-amyl.
 10. The process according to claim 6, wherein in saidmetallocene of the general formula (1), m is
 2. 11. The processaccording to claim 6, wherein in said metallocene of the general formula(1), M is Zr.
 12. The process according to claim 6, wherein in saidmetallocene of the general formula (1), X is a halogen atom and/or aC₁-C₈ hydrocarbyl group.
 13. The process according to claim 6,comprising contacting said metallocene a) of the general formula (1)which has the following structural formula (3)

wherein each of the Y₁''s and Y₂'s is the same or different and is oneof a hydrogen atom, a halogen atom, an acyl group, an acyloxy group, asubstituted or unsubstituted C₁-C₁₀ hydrocarbyl group, an —OR, —SR, —NR,—C(H or R)═, or —PR₂ radical, R being one of a C₁-C₁₆ hydrocarbyl groupor a tertiary substituted-C₁-C₈ hydrocarbylsilyl group, provided that atleast one of the Y₁'s and Y₂'s is one of said —OR, —SR, —NR, —C(H orR)═, or —PR₂ radicals; Z is a bivalent atom or group having at least onechain atom which is one of a carbon, silicon, oxygen, sulphur, nitrogen,or phosphorus atom, preferably 1-4 carbon and/or silicon chain atoms;each R″ is the same or different and is one of a hydrogen atom, ahalogen atom, a C₁-C₁₀ hydrocarbyl group, or ring constituent or aC₁-C₁₀ hydrocarbyloxy group, M is one of Ti, Zr, or Hf; and X₁ and X₂are the same or different and are one of a halogen atom and a C₁-C₈hydrocarbyl group.
 14. The process according to claim 6, wherein saidmetallocene of the formula (1) or (3) isethylene-bis(2-tert-butyldimetylsiloxy-indenyl)zirconium dichloride. 15.The process according to claim 6, wherein said metallocene of theformula (1) or (3) is dissolved in a chlorinated or unchlorinated C₄-C₁₀hydrocarbon solvent such as hexane or toluene.
 16. The process accordingto claim 6, wherein in the formulas (2), said R′ is a C3-C10 alkyl groupand, independently, 2≦p≦12.
 17. The process according to claim 16,wherein the aluminoxane of the formulas (2) ishexa(isobutylaluminoxane).
 18. The process according to claim 6, whereinthe aluminoxane of the formulas (2) is dissolved or immersed in achlorinated or unchlorinated C4-C10 hydrocarbon solvent.
 19. The processaccording to claim 6, wherein the molar ratio Al/M between thealuminoxane aluminium and the metallocene transition metal is between 20and
 2000. 20. The process according to claim 6, wherein theconcentration of the metallocene in the catalyst composition isregulated to between 0.01 and 100 mmol/l.
 21. A homogeneous olefinpolymerization catalyst composition, wherein said catalyst compound hasbeen prepared according to claim
 6. 22. A method of olefinpolymerization comprising contacting an olefin with a metallocenealuminoxane catalyst composition, characterized in that as said catalystcomposition is used a metallocene pro-catalyst containing aring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligandas defined in claim 1 and an aluminoxane cocatalyst containing alkylgroups containing at least two carbon atoms or the reaction productthereof.
 23. A method of olefin polymerization comprising contacting ametallocene containing ring-substituted homo- or heterocycliccyclopentadienyl sandwich ligand as a pro-catalyst as defined in claim 1with an aluminoxane cocatalyst containing at least two carbon atoms. 24.A composition according to claim 5, wherein said Z bivalent atom orgroup has 1-4 carbon or silicon chain atoms.
 25. A composition accordingto claim 5, wherein said Z bivalent atom or group has 1-4 carbon andsilicon chain atoms.
 26. The process according to claim 6, wherein insaid metallocene of the general formula (1), m is 2 and the two Cpligands are bridged with each other by a bivalent atom or group Z havingat least one chain atom which is one of a carbon, silicon, oxygen,sulphur, nitrogen or phosphorus atom.
 27. The process according to claim6, wherein in said metallocene of the general formula (1), wherein m is2 and Z is ethylene or silylene.
 28. The process according to claim 12,wherein said X is chlorine.
 29. The process according to claim 12,wherein said X is methyl.
 30. The process according to claim 6, whereinsaid metallocene isethylene-bis(2-tert-butyldimethylsiloxyindentyl)zirconium dimetheyl or atetrahydroanalog thereof.
 31. The process according to claim 16, whereinsaid R′ C3-C10 alkyl group is an isopropyl, isobutyl, sec-butyl,tert-butyl, isoamyl, sec-amyl, or tert-amyl group.
 32. The processaccording to claim 16 or 31, wherein said p is ≦4 and ≦8.
 33. Theprocess according to claim 18, wherein said hydrocarbon solvent ishexane or toluene.
 34. The process according to claim 19, wherein saidmolar ratio Al/M is between 50 and
 1500. 35. The process according toclaim 19, wherein said molar ratio Al/M is between 100 and
 1200. 36. Theprocess according to claim 6, wherein the concentration of themetallocene in the catalyst composition is regulated to between 0.5 and10 mmol/l.
 37. The process according to claim 6, wherein theconcentration of the metallocene in the catalyst composition isregulated to between 1 and 5 mmol/l.
 38. The process according to claim16, wherein the aluminoxane of formulas (2) istetra(isobutylaluminoxane).